1. Field of the Invention
The present invention relates to a new type nonvolatile memory element or cell including a superconductor ring. More precisely, it relates to a new concept of the nonvolatile memory element or cell comprising a superconductor ring and a MOSFET.
In a preferred embodiment, the nonvolatile memory according to the present invention includes a superconductor ring composed of compound oxide or metal oxide complex possessing a high critical temperature of superconductivity.
2. Description of the Related Art
The nonvolatile memory for computers or information processing systems can held information even after a power supply is turned off.
The conventional memory element or cell for the nonvolatile memories is constructed by a semiconductor element which can store electrostatic charge such as MNOS (metal-nitride-oxide-semiconductor) or MAOS (metal-alumina-oxide-semiconductor) or by a semiconductor element which utilizes avalanche or tunnel effect such as FAMOS (floating-gate avalanche-injection MOS) or MNOS (metal-nitride-oxide semiconductor). These semiconductor memories are used widely as PROM in computers.
In the above-mentioned conventional semiconductor memories, information is stored basically in a form of charge. Therefore, if the charge is neutralized or lost, the information is also lost. Still more, the trapped electrons disappear under strong irradiation of X-ray or UV ray. In other words, irradiation of X-ray or UV ray can be used for erasing FAMOS. However, FAMOS can not be erased by electrical mode. In the case of MNOS and MAOS, holding time of information is limited.
Now, the present inventors propose a new concept of the nonvolatile memory element or cell which can hold or store information in a form of permanent current in a superconductor ring.
Therefore, an object of the present invention is to provide a novel memory element or cell including at least one superconductor ring.